Remove IXFA_Parser, cleanup XFA parser code.

xfa/fxfa/parser/xfa_parser.h

-// Copyright 2014 PDFium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
-
-#ifndef XFA_FXFA_PARSER_XFA_PARSER_H_
-#define XFA_FXFA_PARSER_XFA_PARSER_H_
-
-#include "xfa/fxfa/parser/xfa_document.h"
-
-class CFDE_XMLDoc;
-
-class IXFA_Parser {
- public:
-  static IXFA_Parser* Create(CXFA_Document* pFactory,
-                             FX_BOOL bDocumentParser = FALSE);
-
-  virtual ~IXFA_Parser() {}
-  virtual void Release() = 0;
-  virtual int32_t StartParse(IFX_FileRead* pStream,
-                             XFA_XDPPACKET ePacketID = XFA_XDPPACKET_XDP) = 0;
-  virtual int32_t DoParse(IFX_Pause* pPause = nullptr) = 0;
-  virtual int32_t ParseXMLData(const CFX_WideString& wsXML,
-                               CFDE_XMLNode*& pXMLNode,
-                               IFX_Pause* pPause = nullptr) = 0;
-  virtual void ConstructXFANode(CXFA_Node* pXFANode,
-                                CFDE_XMLNode* pXMLNode) = 0;
-  virtual CXFA_Document* GetFactory() const = 0;
-  virtual CXFA_Node* GetRootNode() const = 0;
-  virtual CFDE_XMLDoc* GetXMLDoc() const = 0;
-  virtual void CloseParser() = 0;
-};
-
-#endif  // XFA_FXFA_PARSER_XFA_PARSER_H_